Various bearing assemblies are known in the art. Typical bearing assemblies include a circumferential inner race mounted on an inner component, for example, a rotating inner member such as a shaft, and an outer race positioned so that the inner race is in an opposed and spaced apart relation from the outer race. The outer race is mounted to an outer component, such as for example, a stationary member. A plurality of roller elements, such as balls, is typically disposed between the inner race and the outer race. The roller elements reduce friction and wear between the moving parts and surfaces, and the bearing assembly often contains a lubricant to further protect the roller elements and other parts by reducing friction and wear. Exemplary bearing assemblies are disclosed in U.S. Pat. No. 5,704,719 (Cook et al.), U.S. Pat. No. 5,716,147 (Cook et al.), U.S. Pat. No. 5,863,137 (Johnson et al.), U.S. Pat. No. 5,927,864 (Feerick), and U.S. Pat. No. 6,677,283 (Ni), all of which are incorporated herein by reference.
Bearing assemblies are often subjected to harsh operating environments where the bearing assemblies are exposed to liquid, gaseous, and solid contaminants. For example, bearing assemblies often encounter dirt, abrasive materials, metal particles, corrosive chemicals, and water. Contaminants that migrate into the bearing assembly interior can quickly cause damage and wear to the roller elements that can ultimately result in bearing failure.
Various sealing arrangements have been described in the art to protect bearing assemblies. A typical sealing arrangement can operate to reduce the entry of contaminants into the bearing assembly where the roller elements are located. Often sealing arrangements include rigid sealing elements that typically have one or more metallic circumferential flanges associated with the inner or outer component and are closely positioned with respect to a cooperating rigid feature of the other component. However, in many applications, bearing assemblies can encounter or generate temperature changes during operation that result in thermal expansion and/or movement between components of the bearing assembly.
Thermal expansion can result in axial and/or radial expansion, thereby causing movement of various bearing assembly components relative to each other which can change the effectiveness of a bearing assembly seal. For example, axial and/or radial expansion due to heating and/or wear of the bearing assembly and inner member can result in the creation of an overly large gap in a bearing assembly seal. Such axial and/or radial expansion can also result in bearing assembly sealing components being brought into contact with each other and to wear against each other, or to otherwise damage the seal or components. Consequently, the seal's effectiveness in excluding contaminants and/or in retaining lubricant within the bearing assembly can be compromised.